class Top{
	public Top(String s){
		System.out.print("B");
	}
}

public Programa6 extends Top{
	public Programa6(String s){
		System.out.print("D");
	}
	public static void main(String [] args){
	Programa6 p = new Programa6("C");
	System.out.print(p);
	}
}